Self assembling proteins as technology platform for the development of new bio-composite materials

Self assembly is a widespread phenomenon in nature. We are working with bacterial surface layer proteins which represent the outermost cell envelope of many bacteria and almost all archaea. Our bacteria were isolated from a uranium mining waste pile and are therefore adapted to high contents of heavy metals. Most of them feature surface layer proteins possessing high metal binding capacities. Bacterial surface layer (S-layer) proteins exhibit self organizing properties combined with the ability to arrange at interfaces. In vitro they form a paracrystalline protein lattice with defined pores and cavi-ties as it can be naturally found on the bacterial surface. Our effort is to use the special properties of these proteins for the design of nano structured and functionalized com-posites. Current workings are focused on catalytic materi-als and sensory layers. We use the self assembling proper-ties for coating various substrates by recrystallizing pro-tein monomers direct on surfaces. The metal binding abil-ities of the lattice can be used for filtering or to form met-al nanoparticles of uniform size and distribution in the pores of the protein layer. The amino acid residues of the protein are suitable for linking further functional mole-cules to the lattice with high density